China is rich in coal resources. Coal is also a main energy source and raw material for consumption in China, and it will always dominates in energy sources in the current and future period. Therefore, whether the coal mining industry can develop healthily and steadily will directly affect further improvement and development of all walks of life in China.
The health state of a shearer, as one important mining equipment in underground coal mines, is directly related to efficient and safe mining of coal mines. Since the shearer operates all year round in high-dust concentration, high-impact load, high-temperature and high-pressure, and humid environment, the stability and reliability thereof will be affected by the harsh environment. Once a fault occurs, production halts will be caused in the entire fully-mechanized mining face, thereby leading to considerable economic damage. Therefore, the health state of the shearer must be monitored in real time.
A drum is a mechanism for coal cutting, coal dropping and coal loading directly on the shearer, and it is essential to ensure normal, safe and smooth operation of the drum in order to guarantee the efficiency of coal mining. As a typical rotating machine, the drum is prone to axial misalignment, structural fracture and other faults, and 80% of the faults can be reflected by vibration anomalies. Therefore, a vibration signal of the drum contains rich state information, so it is necessary to monitor the vibration signal of the shearer drum in real time without shutdown or disassembly, and the vibration signal is analyzed to determine the deterioration degree and fault nature of the shearer drum.
In current practical applications, the indirect method is generally adopted for vibration monitoring of the shearer drum, that is, a sensor and a monitoring system are mounted on a mechanical structure and a power device (such as a ranging arm) near the shearer drum and directly associated with the shearer drum, and an electrical vibration sensor and monitoring system are generally adopted. Researches show that synchronous monitoring of radial and axial vibration of the shearer drum is difficult to realize with such an indirect monitoring method in practical applications, and the monitoring process is easily interfered by a strong electromagnetic field in the fully-mechanized mining face, so that the monitoring sensitivity is low, and thus the health state of the shearer drum cannot be directly and accurately reflected.